The present disclosure relates to exemplary methods and devices for supplying a coating system with a particulate auxiliary material. This relates, for example, to a system for the automatic painting of vehicle bodies or parts thereof, e.g., by using painting robots.
Methods and apparatuses of this generic type are generally known, for example as described by WO 2007/039276 A1 and WO 2007/039275 A1 as well as from DE 10 2005 013 708 A1, DE 10 2005 013 709 A1, DE 10 2005 013 710 A1 and DE 10 2005 013 711 A1, each of which are hereby expressly incorporated by reference in their entireties. In accordance with these systems, the dry separation of the wet paint overspray from the exhaust air stream from the spray booth is effected in a filter apparatus after a flowable, particulate, so-called pre-coat material has been previously dispensed into the exhaust air stream by means of a nozzle arrangement. The purpose of the pre-coat material in these examples is for it to be deposited as a barrier layer on the filter surfaces in order to prevent these surfaces from clogging due to adhering overspray particles. For examples, lime, rock meal, aluminium silicates, aluminium oxides, silicon oxides, powder paint or the like are used as pre-coat material which is separated in the filter apparatus with the overspray. By periodically cleaning the filter apparatus, the mixture consisting of pre-coat material and wet paint overspray enters into reception containers, from where it can be partly directed to a renewed use as a pre-coat material. The reception containers are distributed beneath the application region over the entire horizontal booth cross-sectional surface. The nozzle arrangement dispensing the pre-coat material into the exhaust air stream is supplied by means of an injector from a feed container containing the pre-coat material in a flowable state.
Another method of the generic type mentioned above is generally disclosed by DE 4211465 C2 which is used for the dry separation, recovery and processing of a mist incident in spray painting operations and consisting of sticky paint particles from the exhaust air stream. This method involves the addition of a paint-compatible auxiliary dusty substance geared towards the recovery of the separated mist. Colour pigments or inorganic filler materials are to be used as paint-compatible auxiliary dusty substances. For the purposes of recovery, one part of the recovered auxiliary dusty substance is reintroduced into the circuit through the booth whilst the other part is discharged for processing this proportion to form new paint with the addition of fresh paint raw materials and/or solvents, and is supplemented by a fresh auxiliary dusty substance. The auxiliary dusty substance is injected by way of nozzles into a mixing chamber disposed beneath the application region, where the dust particles accumulate on the overspray particles in the booth air flowing through the mixing chamber. The exhaust air mist, pre-treated in this manner, from the mixing chamber is supplied to a filtering separator via an exhaust line and from there the part of the auxiliary dusty substance reintroduced into the booth circuit enters into an auxiliary dusty substance storage bin where it is mixed with a fresh auxiliary dusty substance which has been supplied in a metered manner. This mixture of fresh and recovered auxiliary dusty substances is forced, by a pneumatic transmitter, into a conveying line leading to the nozzles of the mixing chamber beneath the application region.
Accordingly, there is a need for a method and a device for supplying the coating system with the particulate auxiliary material which permit an improved charging of the overspray particles with the auxiliary material and simultaneously enable the auxiliary material to be conveyed in a particularly purposeful manner.